1. Field of the Invention
This invention relates generally to tamper bands for container end caps, and more particularly to a tamper band having an engagement member on its interior surface which is flexible and provides gripping of a substantially cylindrical or rectilinear portion of the container neck during removal of the end cap to restrict axial movement of the tamper band, enable severing of a frangible connection between the tamper band and the end cap and retain the tamper band on the container after removal of the end cap to provide evidence of tampering.
2. Description of the Related Art
In order to sever a frangible connection between a tamper band and an end cap affixed to a container neck, axial movement of the tamper band with respect to the end cap must be restricted as the end cap is removed. To restrict such axial movement, the container neck typically requires modification to include a tamper band engagement flange about its periphery which abuts the tamper band during removal of the end cap.
Examples of such tamper bands are illustrated in U.S. Pat. Nos. 4,470,513 and 4,478,343 each of which discloses a tamper-indicating closure having an annular lower portion which includes a plurality of spaced apart tabs connected by way of flexible webs and having a projection on each tab. The container includes a neck portion having an annular flange below the threads on the neck including an upper annular surface which is sloped downwardly to meet an essentially horizontal lower annular surface. During removal of the closure, the projections of the tabs interfere with the horizontal lower annular surface of the annular flange to prevent removal of the tamper band and provide severing of the frangible connection. To ensure that the tabs of the annular lower portion make good interfering contact with the annular container flange, the closure can be modified to vary the positioning of the annular lower portion with respect to the annular upper portion of the tamper band or by providing projections on the tabs and/or on the lower inside part of the annular upper portion of the tamper band.
It therefore is desirable to provide a tamper band having an engagement member on its interior surface which engages a substantially cylindrical or rectilinear portion of the container neck to restrict axial movement of the tamper band, enable severing of the frangible connection between the tamper band and the end cap and retain the tamper band on the container neck to provide visible indication of tampering to a user after the end cap is removed.